It seems like each article takes a lot of vertical space. What if you changed the UI so you just displayed a title for each article with a little icon next to it like a downward arrow that you could click on if you wanted to see more of that article? That way, you could display more titles on one screen so that the user could more quickly scroll to the articles they actually wanted to see?
The arrows in the circles floating fixed at the bottom expand and collapse as you want.
Yes there is a collapse all button on the bottom right. On desktop view you can also try the table/card view switch button next to the "sort by" button for denser information.